This invention relates generally to apparatus for producing tufted textile goods such as carpet, upholstery, and the like, and more particularly to improved tufting apparatus capable of producing patterned tufted goods.
U.S. Pat. No. 4,549,496 which issued Oct. 29, 1985, to Kile discloses highly advantageous tufting apparatus for producing patterned tufted goods using yarns of different colors or different textures. This apparatus is capable of placing yarn into a backing to create patterns and designs which previously were generally available only from a weaving loom or by using printing techniques. The patented apparatus employs multiple heads spaced across the width of a backing material. Each head comprises a reciprocating backing opener tube for penetrating the backing and for implanting yarn tufts in the backing by feeding yarn through the tube pneumatically. The backing opener is connected to a yarn exchanger into which a plurality of yarns of different colors, for example, are supplied, and a mechanism is included which enables the selection of one or more of the yarns for implantation into the backing for each penetration by the backing opener. The multiple heads are stepped in synchronism across the backing for a distance corresponding to the spacing between the heads in order to implant a transverse row of yarn tufts. The backing is then advanced to the position of the next row and the process is repeated to implant the next row. A computer controls the selection of the yarn implanted by each backing opener for each penetration of the backing in order to produce a desired pattern in the finished goods.
Although the patented apparatus represents a significant advancement in the tufting industry in that it has enabled the production of multicolored and patterned tufted goods at a substantially reduced cost and in a substantially shorter period of time than is possible with conventional weaving looms, it is desirable to improve tufting apparatus embodying the patented invention to reduce costs and further increase production speed. One area in which improved efficiency is desired in practical apparatus embodying the patented invention is in the mechanism which cuts the yarn after it has been implanted into the backing. This was addressed in the aforesaid copending U.S. application Ser. No. 07/366,545 filed June 15, 1989, which disclosed an improved yarn cutting mechanism having significant advantages over that disclosed in the Kile patent by providing a cutting mechanism wherein a cutting blade cooperates with the backing opener tube or needle and shears the yarn as the hollow needle reciprocates into shearing engagement with the blade and the blade acts against the angled surface forming the needle point. Additionally, the cutting apparatus disclosed in the aforesaid copending patent application includes mechanism for permitting the yarn to be selectively cut or not cut as desired so that loop pile, cut pile, and cut/loop pile fabrics may be produced.
A significant factor influencing the production speed of practical apparatus embodying the invention of the Kile patent is the number of tufting heads embodied in the apparatus. The greater the number of heads, the less distance each head must traverse and, accordingly, the faster a row of tufts can h=implanted in the backing. As the number of heads increases, however, other problems arise. The increased weight makes it more difficult to move the heads accurately and to maintain their alignment and positions relative to one another. Additionally, in the aforesaid patent application rather than the multiple heads which carry the hollow needle being moved across the backing, the backing is shifted transversely so that substantially less weight is moved transversely which not only simplifies the transverse shifting apparatus but also provides greater accuracy to the yarn placement.
A significant factor influencing the cost and accuracy of tufting apparatus embodying the invention of the Kile patent is the control over the feeding of the yarn to the hollow needle. The feeding of the yarn must be positive, and when a yarn change is to be made for a particular needle the yarn previously stitched by that needle should be positively withdrawn from the needle so that the subsequent yarn will not be blocked by the previously sewn yarn. Unless this withdrawal of the previously sewn yarn is assured, a substantially greater air pressure is required to supply the subsequent yarn through the needle. Greater pressure requirements, of course, result in larger compressers and more costly machine and production costs. Additionally, when the yarn is withdrawn from the needle, unless the yarn withdrawal is controlled, the next time that yarn is required to be fed to the needle an accurate and consistent length of yarn can not be assured. This would result in requiring additional pressure to assure that a sufficient length of yarn is supplied. The effect is that a larger than required amount of pressure must be utilized, and if too much yarn is supplied to the needle additional yarn shearing operations are required for producing a satisfactory product. The additional pressure results in increased cost, as does the additional shearing operations.
It is desirable to provide tufting apparatus which avoids the foregoing problems and which affords further improvements in tufting apparatus of the type disclosed in the Kile patent, and it is to these ends that the present invention is directed.